The present invention relates generally to soap dispensers and, more particularly, to a liquid soap dispenser having a fluid level sensor.
Soap dispensers commonly used with commercial lavatory systems generally consist of a vessel or container for holding a volume or supply of liquid soap, a nozzle, and a tube connecting the nozzle to the vessel. The nozzle will typically be mounted to a wall or backsplash adjacent a wash basin, a countertop supporting the wash basin, or the wash basin itself. The vessel that holds the supply of liquid soap is typically a refillable container and is commonly mounted to the underside of the wash basin or below a countertop, such as in cabinetry supporting the countertop. A given vessel can be used to supply liquid soap to a single nozzle or to multiple nozzles. Liquid soap dispensers are commonly found in high traffic washrooms like those of shopping malls and centers, schools and universities, airports and bus/rail depots, concert and sport arenas, stadiums, movie theaters and playhouses, parks, and restaurants.
Maintenance personnel are typically charged with periodically inspecting the liquid soap supply to ensure that the level of liquid soap is sufficient to meet the expected short-term demand. This typically requires maintenance personnel to either remove the liquid soap supply container from its position underneath the wash basin, kneel down to a potentially discomforting physical position that allows the fill level of the container to be seen, or remove a spout that allows for a bird's eye view of the inside of the supply container. Whether kneeling down to visually inspect the fill level or taking a bird's eye view, it can be difficult for the person to accurately determine the fill level.
Given these and other difficulties in determining the amount of liquid soap remaining in a given container, it is not uncommon for maintenance personnel to either ignore their responsibility altogether until notified by a visitor that liquid soap is unavailable at one or more of the wash basins or “top off” the liquid soap supply with each check of the fill level. While the latter is certainly preferred over the former from a customer service level, constantly topping off the soap container with replenishing soap adds to the man-hours required to service a washroom.
Another drawback of conventional liquid soap containers is that the placement of the container(s) is often adjacent the wall to which the wash basin is mounted. This placement typically results in the liquid soap container being mounted roughly three feet away from the outer edge of the wash basin or countertop, which can make it very difficult for a service person to visually determine how much liquid soap remains in the container. Moreover, during refilling, it is not uncommon for an excess volume of liquid soap to be poured into the container resulting in an overflow condition that can be messy, wasteful, and costly. It can also lead to the corrosion of parts and increase bacteria collection.
Accordingly, fill level sensors have been developed to measure the level of soap in a container and provide feedback to service personnel without requiring the serviceperson to visually inspect the liquid soap supply. Most of these sensors use costly optics, infrared devices, reed switches, or magnet arrangements to measure the fill level. Since a facility can have several, if not dozens, of wash basins, soap dispensers, and liquid soap supply containers, the added cost of the fill level sensors can be quite impactful and, in some instances, cost prohibitive.
One proposed solution, as described in U.S. Pat. No. 4,610,165, is to use an inclinometer mounted to a float-bearing member that changes elevations in response to volume changes within a liquid soap container. Inclinometers have commonly been used to measure the tilt of a member in relation to gravity. Moreover, conventional inclinometers are advantageously insensitive to movements other than tilt and therefore are generally considered accurate in determining tilt. Additionally, since the output of an inclinometer as a function of tilt angle is typically linear, inclinometers are considered to provide a high resolution output. However, the accuracy and precision of inclinometers often make such devices costly. When incorporated into a liquid soap dispenser, this cost is magnified for facilities, such as malls, schools and universities, stadiums and arenas, offices, and the like that have several, if not dozens, of soap dispensers.